<template>
  <div class="home-page">

  <div class="banner">
    <div class="container">
      <h1 class="logo-font">conduit</h1>
      <p>A place to share your knowledge.</p>
    </div>
  </div>

  <div class="container page">
    <div class="row">

      <div class="col-md-9">
        <div class="feed-toggle">
          <ul class="nav nav-pills outline-active">
            <li v-if="user" class="nav-item">
              <nuxt-link
                class="nav-link"
                :class="{
                  active: tab === 'your_feed'
                }"
                exact
                :to="{
                  name: 'home',
                  query: {
                    tab: 'your_feed'
                  }
                }">Your Feed</nuxt-link>
            </li>
            <li class="nav-item">
              <nuxt-link
                class="nav-link"
                :class="{
                  active: tab === 'global_feed'
                }"
                exact
                :to="{
                  name: 'home',
                  query: {
                    tab: 'global_feed'
                  }
                }">Global Feed</nuxt-link>
            </li>
            <li v-if="tag" class="nav-item">
              <nuxt-link
                class="nav-link"
                :class="{
                  active: tab === 'tag'
                }"
                exact
                :to="{
                  name: 'home',
                  query: {
                    tab: 'tag',
                    tag: tag
                  }
                }"
              >#{{ tag }}</nuxt-link>
            </li>
          </ul>
        </div>

        <div
          class="article-preview"
          v-for="article in articles"
          :key="article.slug"
        >
          <div class="article-meta">
            <nuxt-link :to="{
              name: 'profile',
              params: {
                username: article.author.username
              }
            }">
              <img
                :src="article.author.image"
              />
            </nuxt-link>
            <div class="info">
              <nuxt-link
                class="author"
                :to="{
                  name: 'profile',
                  params: {
                    username: article.author.username
                  }
                }">
                {{ article.author.username }}
              </nuxt-link>
              <span class="date">{{ article.createdAt | date('MMM DD YYYY') }}</span>
            </div>
            <button class="btn btn-outline-primary btn-sm pull-xs-right"
              :class="{
                active: article.favorited
              }"
              @click="onFavorite(article)"
              :disabled="article.favoriteDisabled"
            >
              <i class="ion-heart"></i> {{ article.favoritesCount }}
            </button>
          </div>
          <nuxt-link
            class="preview-link"
            :to="{
              name: 'article',
              params: {
                slug: article.slug
              }
            }"
          >
            <h1>{{ article.title }}</h1>
            <p>{{ article.description }}</p>
            <span>Read more...</span>
          </nuxt-link>
        </div>

      </div>

      <nav>
        <ul class="pagination">
          <li
            class="page-item"
            :class="{
              active: item === page
            }"
            v-for="item in totalPage"
            :key="item"
          >
            <nuxt-link
              class="page-link"
              :to="{
                name: 'home',
                query: {
                  page: item,
                  tab: $route.query.tab,
                  tag: $route.query.tag
                }
              }">{{ item }}</nuxt-link>
          </li>
        </ul>
      </nav>

      <div class="col-md-3">
        <div class="sidebar">
          <p>Popular Tags</p>

          <div class="tag-list">
            <nuxt-link
              :to="{
                name: 'home',
                query: {
                  tab: 'tag',
                  tag: item
                }
              }"
              class="tag-pill tag-default"
              v-for="item in tags"
              :key="item"
            >{{ item }}</nuxt-link>
          </div>
        </div>
      </div>

    </div>
  </div>

</div>
</template>

<script>
import {
  getArticles,
  getFeedArticles,
  addFavorite,
  deleteFavorite
} from '@/api/article'
import { getTags } from '@/api/tags'
import { mapState } from 'vuex'

export default {
  name: 'HomeIndex',
  watchQuery: ['page', 'tag', 'tab'],
  async asyncData ({ query, store }) {
    const page = Number.parseInt(query.page || 1)
    const limit = 20
    const { tag } = query
    const tab = query.tab || 'global_feed'
    const localArticles = store.state.user && tab === 'your_feed' ?
      getFeedArticles : getArticles
    const [articleRes, tagRes] = await Promise.all([
      localArticles({
        limit,
        offset: (page - 1) * limit,
        tag
      }),
      getTags()
    ])

    const { articles, articlesCount } = articleRes.data
    const { tags } = tagRes.data

    articles.forEach(article => article.favoriteDisabled = false)
    return {
      articles,
      articlesCount,
      tags,
      limit,
      page,
      tag,
      tab: query.tab || 'global_feed'
    }
  },
  computed: {
    ...mapState(['user']),
    totalPage () {
      return Math.ceil(this.articlesCount / this.limit)
    }
  },
  methods: {
    async onFavorite(article) {
      if (!this.user) {
        return
      }
      article.favoriteDisabled = true
      if (article.favorited) {
        await deleteFavorite(article.slug)
        article.favorited = false
        article.favoritesCount += -1
      } else {
        await addFavorite(article.slug)
        article.favorited = true
        article.favoritesCount += 1
      }
      article.favoriteDisabled = false
    }
  }
}
</script>

<style>

</style>